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few hybrid questions

Posted: Tue Dec 02, 2008 3:32 pm
by FishBoy
1. Whats a good C:B ratio for low mix (1-6) hybrids

2. I understand manometric meters are easier to use, how accurate of a pressure guage do I need for one?

3.Would a spark plug be suitable to use in a hybrid?

4. Would a quick disconnect be safe to use on a hybrid (for meter hook-up)?

5. would copper be safe to use as a barrel?

Posted: Tue Dec 02, 2008 3:50 pm
by jonnyboy
1.It's your preference, how loud do you want it to be? A typical one is about 1.5:1

2.I think dyi said somewhere that his was 40 dollars or so.

3.Possibly,spark gaps are just electrodes for every mix increase the spark will get .5 times smaller. So how big is the gap and what are you using to fire it?

4.Yes, to be safe maybe a a hydraulic one.

5.Yes, copper is excellent.

Posted: Tue Dec 02, 2008 4:48 pm
by ramses
1. CB ratios, play around in hgdt.

2. the good gauges go for $30 on McMaster, but success has been reported with less expensive ones.

3. a gasoline engine is a roughly 8x hybrid, so they should stand up. an ignition coil and 9 volt battery should do the trick(to fire, drag one lead from primary coil across one terminal on 9V with the other connected.

4. and I think the quick disconnects would be acceptable. your hose has a female on it, and male adapters contain no valve, so a ball valve would be needed.

5. copper is good

Posted: Tue Dec 02, 2008 4:55 pm
by mark.f
Spark gap sizes are roughly inversely proportional to the mix number, actually, so for a 4x mix the gap will have to be 1/4 the size at atmospheric pressure, and so on.

Posted: Tue Dec 02, 2008 5:21 pm
by FishBoy
ramses wrote: 2. the good gauges go for $30 on McMaster, but success has been reported with less expensive ones.
Ok, do you have any examples of less expensive ones?
also, how accurate should the guage be, McMaster gives % accuracy on guages
ramses wrote: an ignition coil and 9 volt battery should do the trick(to fire, drag one lead from primary coil across one terminal on 9V with the other connected.
could I trouble you for a diagram?

Posted: Tue Dec 02, 2008 8:49 pm
by CasinoVanart
I used a sparkplug for one of my Hybrids, worked fine up to 9x (limited by compressor).

I also used a quick connect but it was isolated by a 1/2' ball valve, (if the ball valve can handle it the quick connect will be no worries).

My larger Hybrid uses a copper barrel (22mm) no troubles there either. C:B ratios are a personal choice really, i put mine around 2:1 :D Boooooomtastic!

As for the gauge the more accurate it is the better your mix will be, hence a more powerful shot.

Good luck with your build mate :wink:

Posted: Tue Dec 02, 2008 8:54 pm
by FishBoy
CasinoVanart wrote:As for the gauge the more accurate it is the better your mix will be, hence a more powerful shot.

Good luck with your build mate :wink:
Ok, but what would be a reasonable accuracy % range? I just don't know, this is my first hybrid, and I would like to order things soon.

Posted: Tue Dec 02, 2008 9:48 pm
by Gippeto

Posted: Wed Dec 03, 2008 12:01 am
by CasinoVanart
If you can use butane as fuel, it is much more forgiving when fueling up because it combusts at a greater range (3.2% being the ultimate mix iirc) so you will able to tweak it until you find the "sweet spot". Normaly the louder it is, the closer you are getting to a perfect mix :wink:

Posted: Wed Dec 03, 2008 4:06 pm
by ramses
propane is less forgiving, but more powerful and cheaper. you would have to ask spudfarm how much his gauge was. an important thing to look at is the increments of the gauge. if there is a line every 1 psi, it probably won't be giving you accurate mixes. i believe the pressure for manometric metering is .62psi per X.

Posted: Thu Dec 04, 2008 1:05 pm
by jimmy101
ramses wrote:propane is less forgiving, but more powerful and cheaper.
The energy content of propane and butane are basically identical. You wouldn't be able to tell the difference between the two without a chrony and many repeated firings.

Butane is actually a bit cheaper, in a practical way, than is propane. For $0.99 you can get a disposable lighter that's good for a lot of shots. A bernzomatic propane cylinder will give a lot more shots per $$$ but you need about $20 for the first cylinder + torch head.